Facile Synthesis of 1-Methyl-1H-benzo[b]azepines from 1-Methylquinolinium Iodides and Diazo(trimethylsilyl)methylmagnesium Bromide

The reaction of diazo(trimethylsilyl)methylmagnesium bromide, TMSC(MgBr)N2, with 1-methylquinolinium iodides followed by sequential ring expansion using copper(I) chloride gives 1-methyl-3-(trimethylsilyl)-1H-benzo[b]azepines in moderate to good yields. Moreover, the trimethylsilyl group can be removed or converted into a hydroxy(phenyl)methyl group.